Presenter:

Authors:

Nikolaus George Hartman(Univ of British Columbia)

Christian Olsen(Univ of British Columbia)

Saeed Fallahi(Purdue University)

Michael Manfra(Purdue University)

Joshua Folk(Univ of British Columbia)

Entropy measurements, typically derived from bulk properties (e.g. heat capacity), are difficult to access in mesoscopic samples. Taking advantage of a well-known Maxwell relation, we build a mesoscopic device in which it is possible to measure the entropy of quantum states down to the single electron level. To demonstate the efficacy of this method, we apply it to the first few-electron spin states in a gate-defined GaAs quantum dot. The entropy of a single spin (kB ln 2) can be determined within 5% accuracy, as can the entropy at the singlet-triplet crossing for two electrons in a large magnetic field. Looking forward, this measurement approach will be applied to systems with less trivial ground states, such as one or two-channel Kondo systems.